Can someone give me (or point out) the steps I'd go through to remove a spell from my game so that I can reuse the spell name?
I think it's something with Python but I can't find the exact instructions.

TIA.

Maybe using Wrye Bash? But usually, you cannot re-use the custom spell name even if you can delete the spell in-game.

You can definitely fully delete the spell using Wrye Bash, but I can't remember exactly how...

You can also rename the spell too. So if you've deleted a spell using a mod (which doesn't full delete it of course) you might be able to rename the "deleted" spell so you can use the name again.